[SC-05] Build dividends and holders dashboard — distribute, claim, and detokenize

[yusuftomilola]

Overview

The dividends module (contracts/assetsup/src/dividends.rs) distributes revenue to token holders, and detokenization (detokenization.rs) lets holders wind a tokenized asset down — neither has any UI.

What to Build

A Holders & Dividends section within the tokenization tab ([SC-04]):

1. Holders table: address (truncated, copyable), share count, ownership % — from contract reads
2. Dividends (asset admin): deposit/distribute flow per the contract's dividend entrypoints — amount input, wallet-signed, confirmation with tx link
3. Dividends (holder): claimable balance display + claim button (wallet-signed); history of past distributions
4. Detokenization: propose (per detokenization.rs's proposal + 50% majority model), display active proposal with current vote tally, vote buttons for holders — coordinate overlap with [SC-06] (governance UI) so voting components are shared

References

• Contracts: contracts/assetsup/src/dividends.rs, detokenization.rs
• Blocked by [SC-04] (and everything it depends on)

Acceptance Criteria

• Holders and percentages accurate against contract state
• A distribution deposited by the admin becomes claimable by holders, and claiming pays out on testnet
• Detokenization proposal lifecycle (propose → vote → threshold) drivable from the UI
• Every action produces a verifiable tx link